-crash cause recorder fxx ai aircraft



Nov. 16, 1937. s, G, ALLEN 2,099,587

CRASH CAUSE RECORDER FOR AIRCRAFT Filed Jan. 50, 1937 ATTORNEYS PatentedNov. 16, 1937 CRASH causa Mexicanen. rca s Sidney G. en, Raleigh, N. C.

Application .lanuary 30, i937, Serial No. 123,272

i Claims.

This invention relates to crash cause recorders for aircraft.

Hitherto whenever fatal aircraft crashes have occurred no positive clueshave been recoverable from the wreckage to enable investigators to learnthe cause of the crash and thus have an opportunity to correct faultyaircraft construction and prevent future loss of life and'property. Theprimary object of the present invention is to provide a recordingapparatus which will only require the pilot to push a buttoncorresponding` to an indestructible legend designating the approximatecause of a crash which is imminent, unavoidable and certain to happen,to the end that suchdata will be available to authorized personsexamining the wreckage and such probable causes of future crashes may beremedied in future construction as well as in ships in current use.

A further object of the invention is to provide recording apparatus ofthis type including a shield which the pilot may instantly throw overthe recording plungers to -prevent tampering as well as to protect theplungers against destruction by contact with wreckage. Y

A further object is 'to provide novel spring n pressed locking discscorresponding to respective recording plungers, shaped and arranged sothat when the hawk bill of particular plunger is pushed into lockingengagement with its respective disc it will be impossible to release theplunger until the apparatus is taken apart by investigators and at thesame time when one plunger is pushed all remaining plungers arepositively locked against being moved so that'l one cause, and only onedefinite cause, of an impending crash may be recorded by the pilot.

With the above and other objects in view the invention consists ofcertain novel details of construction and combinations of partshereinafter fully described and claimed, it being understood (Gl.liti-135) leased position in full lines and in operative position indotted lines.

Figure ti is a side elevation of the recording apparatus with portionsbroken away to expose the springs for forcing the shield latch into thelatching groove of the cylinder. n

Figure 5 is a fragmentary perspective view showing the hawk bill ofoneoi the plungers.

Referring now to the drawing in which like characters of referencedesignate similar parts in the various views, lll designates a cylinderwhich forms a housing for a plurality of annular locking discs ii whichare conned in axial alignment in the bore of the cylinder by cap nuts i2and i3 which are screw threadedly engaged in the ends of the cylinderand may be sealed in position by pins iti although other sealing meansmay be employed to prevent access to the discs by unauthorized persons.

The discs are mounted in the bore of the cylinder for limited movementendwise of the cylinder'and are' normally held stacked in contact witheach other by a helical spring l5 seated in the recess of the cap nut i3and exerting endwise pressure against the discs li to hold the sameurged against a spacing washer it which abuts the mating cap nut i2, asbest shown in Figure 2.

Each spring pressed annular locking disc il is provided in one end facewith an inturned flange il and the peripheral edges of the disc arerounded off as shown at i8 in Figure 2 to provide a cam surface overwhich a respective recording plunger may pass to depress the discagainst the tension of the spring i5, as will presently appear.

A plunger housing i9 is fixed to extend longitudinally of the cylinderit by screws 20 and pins 2l, passed radially through the plunger housingand into the cylinder, or other means may be used for forming a unitaryassembly of the plunger housing and the cylinder. Projecting laterallyfrom the intersection of the cylinder and the plunger housing is asubstantially rectanguiar panel 22, in the present embodiment or theinvention the panel being interposed at one longitudinal edge betweenthe cylinder and theV plunger housing and being secured in place by theabove mentionedscrews 20 and pins 2 i. The panel is provided withattaching openings 23 for securing the apparatus to the instrument panelof aircraft or in any other locality within convenient reach of thepilot.

A plurality of cylindrical recording plungers 2t equal in number to thenumber of spring pressed locking discs Il, are slidably mounted inannular recesses formed radially 'ln the plunger housing i9. A helicalspring 26 is sleeved on each plunger and is confined under tension in anenlarged cylindrical recess 21 one end of the spring bearing against theinner wall of the recess and the outer end 'of the 'spring bearingagainst a button 28 which is screw threaded onto the plunger. The springtends constantly to hold the plunger at its outer limit of movement.

Each plunger is equipped with a hawk bill 29,

having a base portion of substantially rectangular f vment with the angeI1 of the respective locking disc. one of the plungers is set by thepilot in locking engagement with its respective locking disc no otherplungerfmay thereafter be set since the discs Il have only play enoughto admit one plunger to be interleaved between the discs at which timethe discs are jammed against each other and against the cap nut I3 andrigid washer Consequently one, and only one selected plunger can ever bemoved to locking or recording position.

By referring to'Figure 1 itiwill be noted that legends are disposedlaterally of respective ones of the plungers, such legends indicatingapproximate causes of crashes, such as motor failure, gas leaks, flrebreaking out, lost by instrument failure or the like, and controlcollapse. legends are merely given by way of example as any desiredlegends may be used and any number of plungers and the correspondingnumber of locking discs may be employed as desired. All of the parts arepreferably formed of metal so as to be as nearly as possibleindestructible and the legends'are applied to the panel 20 in anysuitable manner so as to be easily readable in emergencies by a pilot,and to retain as much as possible their legibility after being recoveredfrom wreckage.

As a precaution against tampering, and also to protect the plungers fromdestruction by contact with wreckage, a shield 34 is mounted to rotateabout the axis of the cylinder i0 to a position shown by dotted lines inFigure 3 in which the plunger buttons 28y are embraced by the shield andusually the pilot is supposed to swing this shield to operative positioninstantly after depressing his selected plunger to record the cause of acrash which is imminent, unavoidable, and certain to happen. p

For rotatably mounting the shield on the cylinder a pair of bearingrings 35 are rotatably mounted on shoulders 36 formed on the cap nuts l2and I3 and arcuate supporting arms 31 are riveted to the rings as shownat 38 or otherwise secured in place. The arcuate arms are bridged by abar 39 which is integral with the shield 34, as best shown in Figure 3,and is provided with housings 40 in which helical springs 4i aredisposed. These 1 helical springs 4i bear upon one flange of a channeledlatch member 42 which is slidably mounted on the underneath face of thebar` 39, and hold saidflange in frictional' engagement with thecylindrical wall of the cylinder I0. During rota- As best shown inFigure 2, when any` These tion of the shield on its axis to a positiontoembrace and protect the plungers, the springs 4I will force said flangeof the latch into a latching groove 43 formed longitudinally in the wallof the cylinder so that the shield is yieldably held in its operativeposition and cannot be removed from operative position until the matingflangev 44 `of the latch is manually pulled outwardly to release thelatching flange from the latching groove.

In operation the apparatus may be mounted on any suitable part of theaircraft within convenient reach of a pilot. The shield 34 is normallyrocked to released position to expose the plunger buttons 28, in whichposition inturned stop ngers 45, best shown in Figure 4, on the arcuatearms 31, are in position to engage the rear face of the panel 22 andprevent swinging of the shield out of convenient reach of the pilot. Inthe event of an accident involving any failures such as are indicated bythe legends on the panel 22, at the moment.

the pilot decides that a crash is imminent, un'- avoidable, and certainto happen, he may record the defect by quickly pushing in thecorresponding plunger and then instantlyrotating the shield 24 intoposition over the row of plungers. As previously explained, the selectedplunger will interlock with its respective locking disc and cannot bedislodged until authorized persons, investigating the cause of thecrash, remove the sealed cap nuts lI2 and i3 to permit the spring i5 torelease the locking discs. 'I'hus investigators seeking the cause of acrash may have a clue, recoverable from the wreckage, as to the cause ofthe crash, as pointed out by the pilot, and thus have an opportunity tocorrect faulty aircraft construction and prevent future loss of life andproperty in future aircraft construction as well as current aircraft indaily use.

From the above description it is thought that the construction andoperation of the invention will befully understood without furtherexplanation.

What is claimed is:

1. A crash cause recorder for aircraft comprising a supporting cylinder,means for securing the cylinder to aircraft' within convenient reach ofa pilot, spring pressed recording plungers, distinctive legendsassociated with respective plungers designating probablecauses of acrash, and a plurality of locking discs carried by the cylinder andcorresponding to respective plungers, the discs being so shaped andarranged that when a selected plunger is set in locking engagement withits respective disc by a pilot it will be impossible to release the setplunger ers adapted to be selectively operated by a pilot when a crashis imminent, unavoidable, and certain to happen, distinctive legendsassociated with respective plungers designating probable causes of acrash, a plurality of locking discs carried by the cylinder andengageable by and in alignment with respective recording plungers, and aspring controlling the discs to permit sufllcient play between the discsto admit only the one selected plunger to be interleaved be'- tweenvthediscs'when a selected plunger is set by the pilot in locking engagementwith its respective disc and prevent setting of any of the remainingplungers.

3. A crash cause recorder for aircraft ccmprislng a supporting cylinder,cap nuts closing the ends of the cylinder, means for securing thecylinder to the aircraft within convenient reach of a pilot, a plungerhousing extending longitudinally of one side of the cylinder, plungerscarried by the housing and adapted to project into the cylinder, aplurality of locking discs nested in the cylinder between the cap nuts,and a compression spring in the cylinder urging the discs endwise, eachdisc having a locking flange and each plunger having a hawk billextremity engageable with said ange, said hawl; bill being beveled toprovide cam faces adapted to enter between and move apart two adjoiningdiscs whereby the hawk bill of a' selected set plunger will lockinglyengage the ange of a respective locking disc, said spring permittingpredetermined play between the discs so that when a selected plunger isset by the pilot in locking engagement with its respective disc itlected plunger.

will be impossible to release the set plunger or to operate any of theremaining plungers.

4. A crash cause recorder for aircraft cornprising a supportingcylinder, means for securing the cylinder to aircraft'within convenientreach of a pilot, a plurality of recording plungers arranged on oneside` of the cylinder and projecting into the cylinder, locking discs inthe cylinder adapted to be selectively engaged by respective plungerswhen a predetermined plunger is set by a pilot, legends associated withthe plungers designating probable causes of a crash, a shield mountedfor rotation on the axis of the cylinder and adapted to embrace saidplungers and protect the plungers from injury by contact with wreckage,and means for releasably locking the shield to the cylinder, said shieldbeing adapted to be rotated to embrace the plungers by the pilot aftersetting of a se- SIDNEY G. ALLEN.

